The effects of temperature and two different initial pH (2.67 and 7.00) on poly-epsilon-caprolactone (P epsilon CL) nanospheres loaded with flurbiprofen (FB) (aqueous suspensions) were studied to investigate their influence on the stability and physicochemical characteristics of these drug delivery systems. The drug release behavior was also studied. Release of the associated FB occurred very fast on high dilution in a buffered medium. The stability of the polymeric system depends on the temperature and the initial pH value; it is more degradable with the particles stored at 40 degrees C with an initial pH value of 2.67.